1. Field of the Invention
The invention relates to a device for the endoscopic diagnosis and treatment of tissue in humans or animals using a laser.
2. Description of the Prior Art
Endoscopic devices of the previously mentioned type - such a device is known for example from U.S. Pat. No. 5,413,108- are used these days, for example, in rectoscopy. With such a device a slim distal end section of a generally flexible endoscope is introduced into the body via a body opening and is guided up to the location to be diagnosed or to be treated. The tissue region to be diagnosed, for example the wall of the colon, is irradiated by at least two diagnosis lasers of a different wavelength, after which the remitted light, be it either by reflection or by fluorescence, is acquired dependent on wavelength. The receiving signals are linked in a picture element dependent manner by way of subtraction or forming quotients, by which means the topology of the tissue section to be diagnosed is removed, thus by way of these electronic signal linkings, differences in intensity of the received picture, as for example arises with shadows, increases, deepenings and likewise, are removed. The remaining picture or electrical signal permits the desired diagnosis, by way of the wavelength dependent remission appearances of healthy and malignant tissue. After the diagnosis has been effected, the malignant tissue may be directly cauterized by the treatment laser, thus it can be removed. By way of the diagnosis laser directly afterwards, a control may be effected as to whether the malignant tissue has been completely removed or not.
The construction of the device of this known arrangement from U.S. Pat. No. 5,413,108 is such that the diagnosis laser as well as the treatment laser and the receiving means lie outside the endoscope and are connected to the distal endoscope end via an optic fiber. The wavelength separation is effected via filters which lie in a disk which engages in the beam path and can be driven by motor.
A similar arrangement is known from British reference GB 2125986 A. With this device the treatment laser is not led through a separate working channel, but is already integrated.
The disadvantages with the previously mentioned device is in particular the complicated and technically expensive construction. The light emitted by reflection or fluorescence is extremely weak and must be amplified in a technically expensive manner, before it can be received and evaluated. This finally leads to the fact that the diagnosis means has a relatively low sensitivity but also however does not function with the required reliability. Furthermore, with the prior known devices there often arises with the diagnosis, as well as with the therapy, problems with regard to the accuracy of the diagnosis location or therapy location.